X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=osl.c;h=2519228890bc2c25f1b82da6887585afe42840ae;hp=0ac7ead0ffda5ed0925106de589b0bba5c41e706;hb=cd8bb5a2d51179a31842a2cd7012cad28deea78d;hpb=19711eb920137434104f561086d6ba79b6af5eae

diff --git a/osl.c b/osl.c
index 0ac7ead0..25192288 100644
--- a/osl.c
+++ b/osl.c
@@ -1,24 +1,23 @@
 /*
- * Copyright (C) 2007 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2007-2008 Andre Noll <maan@systemlinux.org>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
 
 /** \file osl.c Object storage layer functions. */
-#include "para.h"
-#include "error.h"
-#include "list.h"
-#include "osl_core.h"
 #include <dirent.h> /* readdir() */
 #include <assert.h>
 
-//#define FMT_OFF_T "%li"
-
 
+#include "para.h"
+#include "error.h"
+#include "fd.h"
+#include "list.h"
+#include "osl_core.h"
 /**
  * A wrapper for lseek(2).
  *
- * \param fd The filedescriptor whose offset is to be to repositioned.
+ * \param fd The file descriptor whose offset is to be to repositioned.
  * \param offset A value-result parameter.
  * \param whence Usual repositioning directive.
  *
@@ -41,14 +40,14 @@ int para_lseek(int fd, off_t *offset, int whence)
 }
 
 /**
- * Waraper for the write system call.
+ * Wrapper for the write system call.
  *
  * \param fd The file descriptor to write to.
  * \param buf The buffer to write.
  * \param size The length of \a buf in bytes.
  *
- * This function writes out the given bufffer and retries if an interrupt
- * occured during the write.
+ * This function writes out the given buffer and retries if an interrupt
+ * occurred during the write.
  *
  * \return On success, the number of bytes written is returned, otherwise, the
  * function returns \p -E_WRITE.
@@ -84,11 +83,11 @@ ssize_t para_write(int fd, const void *buf, size_t size)
  */
 ssize_t para_write_all(int fd, const void *buf, size_t size)
 {
-	PARA_DEBUG_LOG("writing %zu bytes\n", size);
+//	PARA_DEBUG_LOG("writing %zu bytes\n", size);
 	const char *b = buf;
 	while (size) {
 		ssize_t ret = para_write(fd, b, size);
-		PARA_DEBUG_LOG("ret: %zd\n", ret);
+//		PARA_DEBUG_LOG("ret: %zd\n", ret);
 		if (ret < 0)
 			return ret;
 		b += ret;
@@ -96,46 +95,6 @@ ssize_t para_write_all(int fd, const void *buf, size_t size)
 	}
 	return 1;
 }
-/**
- * Wrapper for the open(2) system call.
- *
- * \param path The filename.
- * \param flags The usual open(2) flags.
- * \param mode Specifies the permissions to use.
- *
- * The mode parameter must be specified when O_CREAT is in the flags, and is ignored
- * otherwise.
- *
- * \return Positive on success, negative on errors. Possible errors: \p
- * E_EXIST, \p E_ISDIR, \p E_NOENT, \p E_OSL_PERM.
- *
- * \sa open(2).
- */
-int para_open(const char *path, int flags, mode_t mode)
-{
-	PARA_DEBUG_LOG("opening %s\n", path);
-	int ret = open(path, flags, mode);
-
-	if (ret >= 0)
-		return ret;
-	switch (errno) {
-	case EEXIST:
-		ret = -E_EXIST;
-		break;
-	case EISDIR:
-		ret = -E_ISDIR;
-		break;
-	case ENOENT:
-		ret = -E_NOENT;
-		break;
-	case EPERM:
-		ret = -E_OSL_PERM;
-		break;
-	};
-	PARA_ERROR_LOG("failed to open %s: %s\n", path, strerror(errno));
-	return ret;
-}
-
 /**
  * Open a file, write the given buffer and close the file.
  *
@@ -170,7 +129,7 @@ static int append_file(const char *filename, char *header, size_t header_size,
 {
 	int ret, fd;
 
-	PARA_DEBUG_LOG("appending %zu  + %zu bytes\n", header_size, data_size);
+//	PARA_DEBUG_LOG("appending %zu  + %zu bytes\n", header_size, data_size);
 	ret = para_open(filename, O_WRONLY | O_CREAT | O_APPEND, 0644);
 	if (ret < 0)
 		return ret;
@@ -197,54 +156,6 @@ out:
 	return ret;
 }
 
-/**
- * Map a file into memory.
- *
- * \param path Name of the regular file to map.
- * \param open_mode Either \p O_RDONLY or \p O_RDWR.
- * \param obj On success, the mapping is returned here.
- *
- * \return Positive on success, negative on errors. Possible errors include: \p
- * E_FSTAT, any errors returned by para_open(), \p E_EMPTY, \p E_MMAP.
- *
- * \sa para_open(), mmap(2).
- */
-int mmap_full_file(const char *path, int open_mode, struct osl_object *obj)
-{
-	int fd, ret, mmap_prot, mmap_flags;
-	struct stat file_status;
-
-	if (open_mode == O_RDONLY) {
-		mmap_prot = PROT_READ;
-		mmap_flags = MAP_PRIVATE;
-	} else {
-		mmap_prot = PROT_READ | PROT_WRITE;
-		mmap_flags = MAP_SHARED;
-	}
-	ret = para_open(path, open_mode, 0);
-	if (ret < 0)
-		return ret;
-	fd = ret;
-	ret = -E_FSTAT;
-	if (fstat(fd, &file_status) < 0)
-		goto out;
-	obj->size = file_status.st_size;
-	ret = -E_EMPTY;
-	PARA_DEBUG_LOG("%s: size %zu\n", path, obj->size);
-	if (!obj->size)
-		goto out;
-	obj->data = mmap(NULL, obj->size, mmap_prot, mmap_flags, fd, 0);
-	if (obj->data == MAP_FAILED) {
-		obj->data = NULL;
-		ret = -E_MMAP;
-		goto out;
-	}
-	ret = 1;
-out:
-	close(fd);
-	return ret;
-}
-
 /**
  * Traverse the given directory recursively.
  *
@@ -252,9 +163,10 @@ out:
  * \param func The function to call for each entry.
  * \param private_data Pointer to an arbitrary data structure.
  *
- * For each regular file  in \a dirname, the supplied function \a func is
+ * For each regular file under \a dirname, the supplied function \a func is
  * called.  The full path of the regular file and the \a private_data pointer
- * are passed to \a func.
+ * are passed to \a func. Directories for which the calling process has no
+ * permissions to change to are silently ignored.
  *
  * \return On success, 1 is returned. Otherwise, this function returns a
  * negative value which indicates the kind of the error.
@@ -262,37 +174,22 @@ out:
 int for_each_file_in_dir(const char *dirname,
 		int (*func)(const char *, const void *), const void *private_data)
 {
-	DIR *dir = NULL;
+	DIR *dir;
 	struct dirent *entry;
-	/*
-	 * Opening the current directory (".") and calling fchdir() to return
-	 * is usually faster and more reliable than saving cwd in some buffer
-	 * and calling chdir() afterwards (see man 3 getcwd).
-	 */
-	int cwd_fd = open(".", O_RDONLY);
-	struct stat s;
-	int ret = -1;
-
-//	PARA_DEBUG_LOG("dirname: %s\n", dirname);
-	if (cwd_fd < 0)
-		return -E_OSL_GETCWD;
-	ret = -E_OSL_CHDIR;
-	if (chdir(dirname) < 0)
-		goto out;
-	ret = -E_OSL_OPENDIR;
-	dir = opendir(".");
-	if (!dir)
-		goto out;
+	int cwd_fd, ret2, ret = para_opendir(dirname, &dir, &cwd_fd);
+
+	if (ret < 0)
+		return ret == -ERRNO_TO_PARA_ERROR(EACCES)? 1 : ret;
 	/* scan cwd recursively */
 	while ((entry = readdir(dir))) {
 		mode_t m;
 		char *tmp;
+		struct stat s;
 
 		if (!strcmp(entry->d_name, "."))
 			continue;
 		if (!strcmp(entry->d_name, ".."))
 			continue;
-		ret = -E_OSL_LSTAT;
 		if (lstat(entry->d_name, &s) == -1)
 			continue;
 		m = s.st_mode;
@@ -314,41 +211,26 @@ int for_each_file_in_dir(const char *dirname,
 	}
 	ret = 1;
 out:
-	if (dir)
-		closedir(dir);
-	if (fchdir(cwd_fd) < 0 && ret >= 0)
-		ret = -E_OSL_CHDIR;
+	closedir(dir);
+	ret2 = para_fchdir(cwd_fd);
+	if (ret2 < 0 && ret >= 0)
+		ret = ret2;
 	close(cwd_fd);
 	return ret;
 }
 
-int para_mkdir(const char *path, mode_t mode)
-{
-	if (!mkdir(path, mode))
-		return 1;
-	if (errno == EEXIST)
-		return -E_EXIST;
-	if (errno == ENOSPC)
-		return -E_NOSPC;
-	if (errno == ENOTDIR)
-		return -E_NOTDIR;
-	if (errno == EPERM)
-		return E_OSL_PERM;
-	return -E_MKDIR;
-}
-
-static int verify_basename(const char *name)
+static int verify_name(const char *name)
 {
 	if (!name)
-		return -E_BAD_BASENAME;
+		return -E_BAD_NAME;
 	if (!*name)
-		return -E_BAD_BASENAME;
+		return -E_BAD_NAME;
 	if (strchr(name, '/'))
-		return -E_BAD_BASENAME;
+		return -E_BAD_NAME;
 	if (!strcmp(name, ".."))
-		return -E_BAD_BASENAME;
+		return -E_BAD_NAME;
 	if (!strcmp(name, "."))
-		return -E_BAD_BASENAME;
+		return -E_BAD_NAME;
 	return 1;
 }
 
@@ -423,7 +305,7 @@ static int disk_storage_name_of_row(const struct osl_table *t,
 
 static void column_name_hash(const char *col_name, HASH_TYPE *hash)
 {
-	return hash_function(col_name, strlen(col_name), hash);
+	hash_function(col_name, strlen(col_name), hash);
 }
 
 static int init_column_descriptions(struct osl_table *t)
@@ -432,11 +314,11 @@ static int init_column_descriptions(struct osl_table *t)
 	const struct osl_column_description *cd;
 
 	ret = -E_BAD_TABLE_DESC;
-	ret = verify_basename(t->desc->name);
+	ret = verify_name(t->desc->name);
 	if (ret < 0)
 		goto err;
 	ret = -E_BAD_DB_DIR;
-	if (!t->desc->dir)
+	if (!t->desc->dir && (t->num_disk_storage_columns || t->num_mapped_columns))
 		goto err;
 	/* the size of the index header without column descriptions */
 	t->index_header_size = IDX_COLUMN_DESCRIPTIONS;
@@ -451,7 +333,7 @@ static int init_column_descriptions(struct osl_table *t)
 		ret = -E_NO_COLUMN_NAME;
 		if (!cd->name || !cd->name[0])
 			goto err;
-		ret = verify_basename(cd->name);
+		ret = verify_name(cd->name);
 		if (ret < 0)
 			goto err;
 		t->index_header_size += index_column_description_size(cd->name);
@@ -493,10 +375,10 @@ int init_table_structure(const struct osl_table_description *desc,
 	struct osl_table *t = para_calloc(sizeof(*t));
 	int i, ret = -E_BAD_TABLE_DESC, have_disk_storage_name_column = 0;
 
-	PARA_INFO_LOG("creating table structure for '%s' from table "
-		"description\n", desc->name);
 	if (!desc)
 		goto err;
+	PARA_DEBUG_LOG("creating table structure for '%s' from table "
+		"description\n", desc->name);
 	ret = -E_NO_COLUMN_DESC;
 	if (!desc->column_descriptions)
 		goto err;
@@ -526,8 +408,8 @@ int init_table_structure(const struct osl_table_description *desc,
 			break;
 		case OSL_MAPPED_STORAGE:
 			t->num_mapped_columns++;
-			col->index_offset = t->index_entry_size;
-			t->index_entry_size += 8;
+			col->index_offset = t->row_index_size;
+			t->row_index_size += 8;
 			break;
 		case OSL_NO_STORAGE:
 			col->volatile_num = t->num_volatile_columns;
@@ -551,7 +433,7 @@ int init_table_structure(const struct osl_table_description *desc,
 	if (!t->num_rbtrees)
 		goto err;
 	/* success */
-	PARA_INFO_LOG("OK. Index entry size: %u\n", t->index_entry_size);
+	PARA_DEBUG_LOG("OK. Index entry size: %u\n", t->row_index_size);
 	ret = init_column_descriptions(t);
 	if (ret < 0)
 		goto err;
@@ -655,7 +537,7 @@ static int compare_table_descriptions(struct osl_table *t)
 	ret = -E_BAD_TABLE_FLAGS;
 	if (desc.flags != t->desc->flags)
 		goto out;
-	ret = E_BAD_COLUMN_NUM;
+	ret = -E_BAD_COLUMN_NUM;
 	if (desc.num_columns != t->desc->num_columns)
 		goto out;
 	FOR_EACH_COLUMN(i, t->desc, cd1) {
@@ -677,7 +559,7 @@ static int compare_table_descriptions(struct osl_table *t)
 		if (strcmp(cd1->name, cd2->name))
 			goto out;
 	}
-	PARA_INFO_LOG("table description of '%s' matches on-disk data, good\n",
+	PARA_DEBUG_LOG("table description of '%s' matches on-disk data, good\n",
 		t->desc->name);
 	ret = 1;
 out:
@@ -729,10 +611,7 @@ static int create_table_index(struct osl_table *t)
  *
  * \param desc Pointer to the table description.
  *
- * \return Positive on success, negative on errors. Possible errors include: \p
- * E_BAD_TABLE_DESC, \p E_BAD_DB_DIR, \p E_BAD_BASENAME, \p E_NO_COMPARE_FUNC, \p
- * E_NO_COLUMN_NAME, \p E_DUPLICATE_COL_NAME, \p E_MKDIR, any errors returned
- * by para_open().
+ * \return Standard.
  */
 int osl_create_table(const struct osl_table_description *desc)
 {
@@ -749,7 +628,7 @@ int osl_create_table(const struct osl_table_description *desc)
 			continue;
 		if (!table_dir) {
 			ret = para_mkdir(desc->dir, 0777);
-			if (ret < 0 && ret != -E_EXIST)
+			if (ret < 0 && !is_errno(-ret, EEXIST))
 				goto out;
 			table_dir = make_message("%s/%s", desc->dir,
 				desc->name);
@@ -806,14 +685,24 @@ static void mark_table_clean(struct osl_table *t)
 	write_u8(buf, read_u8(buf) & 0xfe);
 }
 
+static void unmap_column(struct osl_table *t, unsigned col_num)
+{
+	struct osl_object map = t->columns[col_num].data_map;
+	int ret;
+	if (!map.data)
+		return;
+	ret = para_munmap(map.data, map.size);
+	assert(ret > 0);
+	map.data = NULL;
+}
+
 /**
  * Unmap all mapped files of an osl table.
  *
  * \param t Pointer to a mapped table.
  * \param flags Options for unmapping.
  *
- * \return Positive on success, negative on errors. Possible errors include:
- * E_NOT_MAPPED, E_MUNMAP.
+ * \return Positive on success, negative on errors.
  *
  * \sa map_table(), enum osl_close_flags, para_munmap().
  */
@@ -825,7 +714,7 @@ int unmap_table(struct osl_table *t, enum osl_close_flags flags)
 
 	if (!t->num_mapped_columns) /* can this ever happen? */
 		return 1;
-	PARA_INFO_LOG("unmapping table '%s'\n", t->desc->name);
+	PARA_DEBUG_LOG("unmapping table '%s'\n", t->desc->name);
 	if (!t->index_map.data)
 		return -E_NOT_MAPPED;
 	if (flags & OSL_MARK_CLEAN)
@@ -836,18 +725,32 @@ int unmap_table(struct osl_table *t, enum osl_close_flags flags)
 	t->index_map.data = NULL;
 	if (!t->num_rows)
 		return 1;
-	FOR_EACH_MAPPED_COLUMN(i, t, cd) {
-		struct osl_object map = t->columns[i].data_map;
-		if (!map.data)
-			continue;
-		ret = para_munmap(map.data, map.size);
-		if (ret < 0)
-			return ret;
-		map.data = NULL;
-	}
+	FOR_EACH_MAPPED_COLUMN(i, t, cd)
+		unmap_column(t, i);
 	return 1;
 }
 
+static int map_column(struct osl_table *t, unsigned col_num)
+{
+	struct stat statbuf;
+	char *filename = column_filename(t, col_num);
+	int ret = -E_STAT;
+	if (stat(filename, &statbuf) < 0) {
+		free(filename);
+		return ret;
+	}
+	if (!(S_IFREG & statbuf.st_mode)) {
+		free(filename);
+		return ret;
+	}
+	ret = mmap_full_file(filename, O_RDWR,
+		&t->columns[col_num].data_map.data,
+		&t->columns[col_num].data_map.size,
+		NULL);
+	free(filename);
+	return ret;
+}
+
 /**
  * Map the index file and all columns of type \p OSL_MAPPED_STORAGE into memory.
  *
@@ -872,7 +775,7 @@ int map_table(struct osl_table *t, enum map_table_flags flags)
 	filename = index_filename(t->desc);
 	PARA_DEBUG_LOG("mapping table '%s' (index: %s)\n", t->desc->name, filename);
 	ret = mmap_full_file(filename, flags & MAP_TBL_FL_MAP_RDONLY?
-		O_RDONLY : O_RDWR, &t->index_map);
+		O_RDONLY : O_RDWR, &t->index_map.data, &t->index_map.size, NULL);
 	free(filename);
 	if (ret < 0)
 		return ret;
@@ -894,20 +797,7 @@ int map_table(struct osl_table *t, enum map_table_flags flags)
 		return num_rows;
 	/* map data files */
 	FOR_EACH_MAPPED_COLUMN(i, t, cd) {
-		struct stat statbuf;
-		filename = column_filename(t, i);
-		ret = -E_STAT;
-		if (stat(filename, &statbuf) < 0) {
-			free(filename);
-			goto err;
-		}
-		if (!(S_IFREG & statbuf.st_mode)) {
-			free(filename);
-			goto err;
-		}
-		ret = mmap_full_file(filename, O_RDWR,
-			&t->columns[i].data_map);
-		free(filename);
+		ret = map_column(t, i);
 		if (ret < 0)
 			goto err;
 	}
@@ -935,7 +825,7 @@ err:	/* unmap what is already mapped */
  * of storage type \p OSL_MAPPED_STORAGE.
  *
  * \return Positive on success, negative on errors. Possible errors include:
- * \p E_BAD_ID, \p E_INVALID_OBJECT.
+ * \p E_BAD_ROW_NUM, \p E_INVALID_OBJECT.
  *
  * \sa osl_storage_type.
  */
@@ -945,17 +835,16 @@ int get_mapped_object(const struct osl_table *t, unsigned col_num,
 	struct osl_column *col = &t->columns[col_num];
 	uint32_t offset;
 	char *header;
-	char *index_entry;
+	char *cell_index;
 	int ret;
 
 	if (t->num_rows <= row_num)
-		return -E_BAD_ID;
-	ret = get_index_entry(t, row_num, col_num, &index_entry);
+		return -E_BAD_ROW_NUM;
+	ret = get_cell_index(t, row_num, col_num, &cell_index);
 	if (ret < 0)
 		return ret;
-	offset = read_u32(index_entry);
-	obj->size = read_u32(index_entry + 4) - 1;
-	PARA_DEBUG_LOG("index_entry: %p\n", index_entry);
+	offset = read_u32(cell_index);
+	obj->size = read_u32(cell_index + 4) - 1;
 	header = col->data_map.data + offset;
 	obj->data = header + 1;
 	if (read_u8(header) == 0xff) {
@@ -963,8 +852,6 @@ int get_mapped_object(const struct osl_table *t, unsigned col_num,
 			obj->size, offset);
 		return -E_INVALID_OBJECT;
 	}
-	PARA_DEBUG_LOG("mapped obj row_num: %u, col %u, size: %zu\n", row_num,
-		col_num, obj->size);
 	return 1;
 }
 
@@ -984,7 +871,7 @@ static int search_rbtree(const struct osl_object *obj,
 		struct osl_object this_obj;
 		parent = *new;
 		if (st == OSL_MAPPED_STORAGE) {
-			ret = get_mapped_object(t, col_num, this_row->id,
+			ret = get_mapped_object(t, col_num, this_row->num,
 				&this_obj);
 			if (ret < 0)
 				return ret;
@@ -1054,7 +941,7 @@ static void remove_rb_node(struct osl_table *t, unsigned col_num,
 	rb_erase(victim, &col->rbtree);
 }
 
-static int add_row_to_rbtrees(struct osl_table *t, uint32_t id,
+static int add_row_to_rbtrees(struct osl_table *t, uint32_t row_num,
 		struct osl_object *volatile_objs, struct osl_row **row_ptr)
 {
 	unsigned i;
@@ -1062,20 +949,18 @@ static int add_row_to_rbtrees(struct osl_table *t, uint32_t id,
 	struct osl_row *row = allocate_row(t->num_rbtrees);
 	const struct osl_column_description *cd;
 
-	PARA_DEBUG_LOG("row: %p, id: %u\n", row, id);
-	row->id = id;
+	row->num = row_num;
 	row->volatile_objects = volatile_objs;
 	FOR_EACH_RBTREE_COLUMN(i, t, cd) {
 		if (cd->storage_type == OSL_MAPPED_STORAGE) {
 			struct osl_object obj;
-			ret = get_mapped_object(t, i, id, &obj);
+			ret = get_mapped_object(t, i, row_num, &obj);
 			if (ret < 0)
 				goto err;
 			ret = insert_rbtree(t, i, row, &obj);
 		} else { /* volatile */
 			const struct osl_object *obj
 				= volatile_objs + t->columns[i].volatile_num;
-			PARA_DEBUG_LOG("inserting %p\n", obj->data);
 			ret = insert_rbtree(t, i, row, obj);
 		}
 		if (ret < 0)
@@ -1109,8 +994,14 @@ static void free_volatile_objects(const struct osl_table *t,
 	for (n = rb_first(&rb_col->rbtree); n; n = rb_next(n)) {
 		struct osl_row *r = get_row_pointer(n, rb_col->rbtree_num);
 		if (flags & OSL_FREE_VOLATILE)
-			for (j = 0; j < t->num_volatile_columns; j++)
-				free(r->volatile_objects[j].data);
+			FOR_EACH_VOLATILE_COLUMN(j, t, cd) {
+				if (cd->storage_flags & OSL_DONT_FREE)
+					continue;
+				free(r->volatile_objects[
+					t->columns[j].volatile_num].data);
+			}
+//			for (j = 0; j < t->num_volatile_columns; j++)
+//				free(r->volatile_objects[j].data);
 		free(r->volatile_objects);
 	}
 }
@@ -1152,7 +1043,7 @@ void clear_rbtrees(struct osl_table *t)
  * \param flags Options for what should be cleaned up.
  *
  * If osl_open_table() succeeds, the resulting table pointer must later be
- * passed to this function in order to flush all changes to the filesystem and
+ * passed to this function in order to flush all changes to the file system and
  * to free the resources that were allocated by osl_open_table().
  *
  * \return Positive on success, negative on errors. Possible errors: \p E_BAD_TABLE,
@@ -1190,13 +1081,13 @@ int osl_close_table(struct osl_table *t, enum osl_close_flags flags)
  */
 int row_is_invalid(struct osl_table *t, uint32_t row_num)
 {
-	char *index_entry;
-	int i, ret = get_index_entry_start(t, row_num, &index_entry);
+	char *row_index;
+	int i, ret = get_row_index(t, row_num, &row_index);
 
 	if (ret < 0)
 		return ret;
-	for (i = 0; i < t->index_entry_size; i++) {
-		if ((unsigned char)index_entry[i] != 0xff)
+	for (i = 0; i < t->row_index_size; i++) {
+		if ((unsigned char)row_index[i] != 0xff)
 			return 0;
 	}
 	PARA_INFO_LOG("row %d is invalid\n", row_num);
@@ -1216,14 +1107,13 @@ int row_is_invalid(struct osl_table *t, uint32_t row_num)
  */
 int mark_row_invalid(struct osl_table *t, uint32_t row_num)
 {
-	char *index_entry;
-	int i, ret = get_index_entry_start(t, row_num, &index_entry);
+	char *row_index;
+	int ret = get_row_index(t, row_num, &row_index);
 
-	PARA_INFO_LOG("marking row %d as invalid\n", row_num);
 	if (ret < 0)
 		return ret;
-	for (i = 0; i < t->index_entry_size; i++)
-		index_entry[i] = 0xff;
+	PARA_INFO_LOG("marking row %d as invalid\n", row_num);
+	memset(row_index, 0xff, t->row_index_size);
 	return 1;
 }
 
@@ -1270,10 +1160,7 @@ int init_rbtrees(struct osl_table *t)
  * The table description given by \a desc should coincide with the
  * description used at creation time.
  *
- * \return Positive on success, negative on errors. Possible errors include:
- * errors returned by init_table_structure(), \p E_NOENT, \p E_STAT, \p \p
- * E_NOTDIR, \p E_BAD_TABLE_DESC, \p E_BAD_DB_DIR, \p E_NO_COMPARE_FUNC, \p
- * E_NO_COLUMN_NAME, errors returned by init_rbtrees().
+ * \return Standard.
  */
 int osl_open_table(const struct osl_table_description *table_desc,
 		struct osl_table **result)
@@ -1293,13 +1180,10 @@ int osl_open_table(const struct osl_table_description *table_desc,
 		ret = stat(dirname, &statbuf);
 		free(dirname);
 		if (ret < 0) {
-			if (errno == ENOENT)
-				ret = -E_NOENT;
-			else
-				ret = -E_STAT;
+			ret = -ERRNO_TO_PARA_ERROR(errno);
 			goto err;
 		}
-		ret = -E_NOTDIR;
+		ret = -ERRNO_TO_PARA_ERROR(ENOTDIR);
 		if (!S_ISDIR(statbuf.st_mode))
 			goto err;
 	}
@@ -1332,7 +1216,7 @@ static int create_disk_storage_object_dir(const struct osl_table *t,
 	dirname = disk_storage_dirname(t, col_num, ds_name);
 	ret = para_mkdir(dirname, 0777);
 	free(dirname);
-	if (ret < 0 && ret != -E_EXIST)
+	if (ret < 0 && !is_errno(-ret, EEXIST))
 		return ret;
 	return 1;
 }
@@ -1359,14 +1243,14 @@ static int append_map_file(const struct osl_table *t, unsigned col_num,
 	int ret;
 	char header = 0; /* zero means valid object */
 
-	PARA_DEBUG_LOG("appending %zu + 1 byte\n", obj->size);
+//	PARA_DEBUG_LOG("appending %zu + 1 byte\n", obj->size);
 	ret = append_file(filename, &header, 1, obj->data, obj->size,
 		new_size);
 	free(filename);
 	return ret;
 }
 
-static int append_index_entry(const struct osl_table *t, char *new_index_entry)
+static int append_row_index(const struct osl_table *t, char *row_index)
 {
 	char *filename;
 	int ret;
@@ -1374,9 +1258,8 @@ static int append_index_entry(const struct osl_table *t, char *new_index_entry)
 	if (!t->num_mapped_columns)
 		return 1;
 	filename = index_filename(t->desc);
-	PARA_DEBUG_LOG("appending %u bytes\n", t->index_entry_size);
-	ret = append_file(filename, NULL, 0, new_index_entry,
-		t->index_entry_size, NULL);
+	ret = append_file(filename, NULL, 0, row_index,
+		t->row_index_size, NULL);
 	free(filename);
 	return ret;
 }
@@ -1426,15 +1309,11 @@ static int delete_disk_storage_file(const struct osl_table *t, unsigned col_num,
 		const char *ds_name)
 {
 	char *dirname, *filename = disk_storage_path(t, col_num, ds_name);
-	int ret = unlink(filename);
+	int ret = unlink(filename), err = errno;
 
-	PARA_INFO_LOG("deleted %s\n", filename);
 	free(filename);
-	if (ret < 0) {
-		if (errno == ENOENT)
-			return -E_NOENT;
-		return -E_UNLINK;
-	}
+	if (ret < 0)
+		return -ERRNO_TO_PARA_ERROR(err);
 	if (!(t->desc->flags & OSL_LARGE_TABLE))
 		return 1;
 	dirname = disk_storage_dirname(t, col_num, ds_name);
@@ -1474,7 +1353,7 @@ int osl_add_and_get_row(struct osl_table *t, struct osl_object *objects,
 	int i, ret;
 	char *ds_name = NULL;
 	struct rb_node **rb_parents = NULL, ***rb_links = NULL;
-	char *new_index_entry = NULL;
+	char *new_row_index = NULL;
 	struct osl_object *volatile_objs = NULL;
 	const struct osl_column_description *cd;
 
@@ -1483,10 +1362,10 @@ int osl_add_and_get_row(struct osl_table *t, struct osl_object *objects,
 	rb_parents = para_malloc(t->num_rbtrees * sizeof(struct rn_node*));
 	rb_links = para_malloc(t->num_rbtrees * sizeof(struct rn_node**));
 	if (t->num_mapped_columns)
-		new_index_entry = para_malloc(t->index_entry_size);
+		new_row_index = para_malloc(t->row_index_size);
 	/* pass 1: sanity checks */
-	PARA_DEBUG_LOG("sanity tests: %p:%p\n", objects[0].data,
-		objects[1].data);
+//	PARA_DEBUG_LOG("sanity tests: %p:%p\n", objects[0].data,
+//		objects[1].data);
 	FOR_EACH_COLUMN(i, t->desc, cd) {
 		enum osl_storage_type st = cd->storage_type;
 		enum osl_storage_flags sf = cd->storage_flags;
@@ -1499,16 +1378,16 @@ int osl_add_and_get_row(struct osl_table *t, struct osl_object *objects,
 		if (sf & OSL_RBTREE) {
 			unsigned rbtree_num = t->columns[i].rbtree_num;
 			ret = -E_RB_KEY_EXISTS;
-			PARA_DEBUG_LOG("checking whether %p exists\n",
-				objects[i].data);
+//			PARA_DEBUG_LOG("checking whether %p exists\n",
+//				objects[i].data);
 			if (search_rbtree(objects + i, t, i,
 					&rb_parents[rbtree_num],
 					&rb_links[rbtree_num]) > 0)
 				goto out;
 		}
 		if (sf & OSL_FIXED_SIZE) {
-			PARA_DEBUG_LOG("fixed size. need: %zu, have: %d\n",
-				objects[i].size, cd->data_size);
+//			PARA_DEBUG_LOG("fixed size. need: %zu, have: %d\n",
+//				objects[i].size, cd->data_size);
 			ret = -E_BAD_DATA_SIZE;
 			if (objects[i].size != cd->data_size)
 				goto out;
@@ -1520,7 +1399,7 @@ int osl_add_and_get_row(struct osl_table *t, struct osl_object *objects,
 	ret = unmap_table(t, OSL_MARK_CLEAN);
 	if (ret < 0)
 		goto out;
-	PARA_DEBUG_LOG("sanity tests passed%s\n", "");
+//	PARA_DEBUG_LOG("sanity tests passed%s\n", "");
 	/* pass 2: create data files, append map data */
 	FOR_EACH_COLUMN(i, t->desc, cd) {
 		enum osl_storage_type st = cd->storage_type;
@@ -1529,12 +1408,12 @@ int osl_add_and_get_row(struct osl_table *t, struct osl_object *objects,
 		if (st == OSL_MAPPED_STORAGE) {
 			uint32_t new_size;
 			struct osl_column *col = &t->columns[i];
-			PARA_DEBUG_LOG("appending object of size %zu\n",
-				objects[i].size);
+//			PARA_DEBUG_LOG("appending object of size %zu\n",
+//				objects[i].size);
 			ret = append_map_file(t, i, objects + i, &new_size);
 			if (ret < 0)
 				goto rollback;
-			update_index_entry(new_index_entry, col, new_size,
+			update_cell_index(new_row_index, col, new_size,
 				objects[i].size);
 			continue;
 		}
@@ -1543,13 +1422,13 @@ int osl_add_and_get_row(struct osl_table *t, struct osl_object *objects,
 		if (ret < 0)
 			goto rollback;
 	}
-	ret = append_index_entry(t, new_index_entry);
+	ret = append_row_index(t, new_row_index);
 	if (ret < 0)
 		goto rollback;
 	ret = map_table(t, MAP_TBL_FL_VERIFY_INDEX);
 	if (ret < 0) { /* truncate index and rollback changes */
 		char *filename = index_filename(t->desc);
-		para_truncate(filename, t->index_entry_size);
+		para_truncate(filename, t->row_index_size);
 		free(filename);
 		goto rollback;
 	}
@@ -1561,11 +1440,11 @@ int osl_add_and_get_row(struct osl_table *t, struct osl_object *objects,
 			volatile_objs[t->columns[i].volatile_num] = objects[i];
 	}
 	t->num_rows++;
-	PARA_DEBUG_LOG("adding new entry as row #%d\n", t->num_rows - 1);
+//	PARA_DEBUG_LOG("adding new entry as row #%d\n", t->num_rows - 1);
 	ret = add_row_to_rbtrees(t, t->num_rows - 1, volatile_objs, row);
 	if (ret < 0)
 		goto out;
-	PARA_DEBUG_LOG("added new entry as row #%d\n", t->num_rows - 1);
+//	PARA_DEBUG_LOG("added new entry as row #%d\n", t->num_rows - 1);
 	ret = 1;
 	goto out;
 rollback: /* rollback all changes made, ignore further errors */
@@ -1583,7 +1462,7 @@ rollback: /* rollback all changes made, ignore further errors */
 	/* ignore error and return previous error value */
 	map_table(t, MAP_TBL_FL_VERIFY_INDEX);
 out:
-	free(new_index_entry);
+	free(new_row_index);
 	free(ds_name);
 	free(rb_parents);
 	free(rb_links);
@@ -1634,18 +1513,18 @@ int osl_get_object(const struct osl_table *t, const struct osl_row *r,
 	if (cd->storage_type == OSL_DISK_STORAGE)
 		return -E_BAD_STORAGE_TYPE;
 	if (cd->storage_type == OSL_MAPPED_STORAGE)
-		return get_mapped_object(t, col_num, r->id, object);
+		return get_mapped_object(t, col_num, r->num, object);
 	/* volatile */
 	*object = r->volatile_objects[t->columns[col_num].volatile_num];
 	return 1;
 }
 
-static int mark_mapped_object_invalid(const struct osl_table *t, uint32_t id,
-		unsigned col_num)
+static int mark_mapped_object_invalid(const struct osl_table *t,
+		uint32_t row_num, unsigned col_num)
 {
 	struct osl_object obj;
 	char *p;
-	int ret = get_mapped_object(t, col_num, id, &obj);
+	int ret = get_mapped_object(t, col_num, row_num, &obj);
 
 	if (ret < 0)
 		return ret;
@@ -1693,14 +1572,14 @@ int osl_del_row(struct osl_table *t, struct osl_row *row)
 		enum osl_storage_type st = cd->storage_type;
 		remove_rb_node(t, i, r);
 		if (st == OSL_MAPPED_STORAGE) {
-			mark_mapped_object_invalid(t, r->id, i);
+			mark_mapped_object_invalid(t, r->num, i);
 			continue;
 		}
-		if (st == OSL_NO_STORAGE)
+		if (st == OSL_NO_STORAGE && !(cd->storage_flags & OSL_DONT_FREE))
 			free(r->volatile_objects[col->volatile_num].data);
 	}
 	if (t->num_mapped_columns) {
-		ret = mark_row_invalid(t, r->id);
+		ret = mark_row_invalid(t, r->num);
 		if (ret < 0)
 			goto out;
 		t->num_invalid_rows++;
@@ -1736,7 +1615,7 @@ static int check_rbtree_col(const struct osl_table *t, unsigned col_num,
  * Lookup \a obj in \a t and return the row containing \a obj. The column
  * specified by \a col_num must have an associated rbtree.
  *
- * \return Positive on success, negative on errors. If an error occured, \a
+ * \return Positive on success, negative on errors. If an error occurred, \a
  * result is set to \p NULL. Possible errors include: \p E_BAD_TABLE, \p
  * E_BAD_STORAGE_FLAGS, errors returned by get_mapped_object(), \p
  * E_RB_KEY_NOT_FOUND.
@@ -1766,9 +1645,12 @@ int osl_get_row(const struct osl_table *t, unsigned col_num,
 static int rbtree_loop(struct osl_column *col,  void *private_data,
 		osl_rbtree_loop_func *func)
 {
-	struct rb_node *n;
+	struct rb_node *n, *tmp;
 
-	for (n = rb_first(&col->rbtree); n; n = rb_next(n)) {
+	/* this for-loop is safe against removal of an entry */
+	for (n = rb_first(&col->rbtree), tmp = n? rb_next(n) : NULL;
+			n;
+			n = tmp, tmp = tmp? rb_next(tmp) : NULL) {
 		struct osl_row *r = get_row_pointer(n, col->rbtree_num);
 		int ret = func(r, private_data);
 		if (ret < 0)
@@ -1780,9 +1662,12 @@ static int rbtree_loop(struct osl_column *col,  void *private_data,
 static int rbtree_loop_reverse(struct osl_column *col,  void *private_data,
 		osl_rbtree_loop_func *func)
 {
-	struct rb_node *n;
+	struct rb_node *n, *tmp;
 
-	for (n = rb_last(&col->rbtree); n; n = rb_prev(n)) {
+	/* safe against removal of an entry */
+	for (n = rb_last(&col->rbtree), tmp = n? rb_prev(n) : NULL;
+			n;
+			n = tmp, tmp = tmp? rb_prev(tmp) : NULL) {
 		struct osl_row *r = get_row_pointer(n, col->rbtree_num);
 		int ret = func(r, private_data);
 		if (ret < 0)
@@ -1802,9 +1687,9 @@ static int rbtree_loop_reverse(struct osl_column *col,  void *private_data,
  * This function does an in-order walk of the rbtree associated with \a
  * col_num. It is an error if the \p OSL_RBTREE flag is not set for this
  * column. For each node in the rbtree, the given function \a func is called
- * with two \p void* pointers as arguments: The first argument points to the
+ * with two pointers as arguments: The first osl_row* argument points to the
  * row that contains the object corresponding to the rbtree node currently
- * traversed, and the \a private_data pointer is passed to \a func as the
+ * traversed, and the \a private_data pointer is passed verbatim to \a func as the
  * second argument. The loop terminates either if \a func returns a negative
  * value, or if all nodes of the tree have been visited.
  *
@@ -1898,16 +1783,14 @@ out:
  *
  * This function  gets rid of all references to the old object. This includes
  * removal of the rbtree node in case there is an rbtree associated with \a
- * col_num. It then inserts \a obj into the table and the rbtree if neccessary.
+ * col_num. It then inserts \a obj into the table and the rbtree if necessary.
  *
  * If the \p OSL_RBTREE flag is set for \a col_num, you \b MUST call this
  * function in order to change the contents of an object, even for volatile or
  * mapped columns of constant size (which may be updated directly if \p
  * OSL_RBTREE is not set).  Otherwise the rbtree might become corrupted.
  *
- * \return Positive on success, negative on errors. Possible errors include: \p
- * E_BAD_TABLE, \p E_RB_KEY_EXISTS, \p E_BAD_SIZE, \p E_NOENT, \p E_UNLINK,
- * errors returned by para_write_file(), \p E_MKDIR.
+ * \return Standard
  */
 int osl_update_object(struct osl_table *t, const struct osl_row *r,
 		unsigned col_num, struct osl_object *obj)
@@ -1920,13 +1803,14 @@ int osl_update_object(struct osl_table *t, const struct osl_row *r,
 		return -E_BAD_TABLE;
 	col = &t->columns[col_num];
 	cd = get_column_description(t->desc, col_num);
+	PARA_DEBUG_LOG("updating column %u of %s\n", col_num, t->desc->name);
 	if (cd->storage_flags & OSL_RBTREE) {
 		if (search_rbtree(obj, t, col_num, NULL, NULL) > 0)
 			return -E_RB_KEY_EXISTS;
 	}
 	if (cd->storage_flags & OSL_FIXED_SIZE) {
 		if (obj->size != cd->data_size)
-			return -E_BAD_SIZE;
+			return -E_BAD_DATA_SIZE;
 	}
 	remove_rb_node(t, col_num, r);
 	if (cd->storage_type == OSL_NO_STORAGE) { /* TODO: If fixed size, reuse object? */
@@ -1938,7 +1822,7 @@ int osl_update_object(struct osl_table *t, const struct osl_row *r,
 		if (ret < 0)
 			return ret;
 		ret = delete_disk_storage_file(t, col_num, ds_name);
-		if (ret < 0 && ret != -E_NOENT) {
+		if (ret < 0 && !is_errno(-ret, ENOENT)) {
 			free(ds_name);
 			return ret;
 		}
@@ -1948,7 +1832,7 @@ int osl_update_object(struct osl_table *t, const struct osl_row *r,
 			return ret;
 	} else { /* mapped storage */
 		struct osl_object old_obj;
-		ret = get_mapped_object(t, col_num, r->id, &old_obj);
+		ret = get_mapped_object(t, col_num, r->num, &old_obj);
 		if (ret < 0)
 			return ret;
 		/*
@@ -1965,18 +1849,22 @@ int osl_update_object(struct osl_table *t, const struct osl_row *r,
 			memcpy(old_obj.data, obj->data, cd->data_size);
 		else { /* TODO: if the size doesn't change, use old space */
 			uint32_t new_data_map_size;
-			char *index_entry;
-			ret = get_index_entry_start(t, r->id, &index_entry);
+			char *row_index;
+			ret = get_row_index(t, r->num, &row_index);
 			if (ret < 0)
 				return ret;
-			ret = mark_mapped_object_invalid(t, r->id, col_num);
+			ret = mark_mapped_object_invalid(t, r->num, col_num);
 			if (ret < 0)
 				return ret;
+			unmap_column(t, col_num);
 			ret = append_map_file(t, col_num, obj,
 				&new_data_map_size);
 			if (ret < 0)
 				return ret;
-			update_index_entry(index_entry, col, new_data_map_size,
+			ret = map_column(t, col_num);
+			if (ret < 0)
+				return ret;
+			update_cell_index(row_index, col, new_data_map_size,
 				obj->size);
 		}
 	}
@@ -2024,7 +1912,7 @@ int osl_open_disk_object(const struct osl_table *t, const struct osl_row *r,
 	filename = disk_storage_path(t, col_num, ds_name);
 	free(ds_name);
 	PARA_DEBUG_LOG("filename: %s\n", filename);
-	ret = mmap_full_file(filename, O_RDONLY, obj);
+	ret = mmap_full_file(filename, O_RDONLY, &obj->data, &obj->size, NULL);
 	free(filename);
 	return ret;
 }
@@ -2071,7 +1959,7 @@ int osl_get_num_rows(const struct osl_table *t, unsigned *num_rows)
  * \param rank Result pointer.
  *
  * The rank is, by definition, the position of the row in the linear order
- * determined by an inorder tree walk of the rbtree associated with column
+ * determined by an in-order tree walk of the rbtree associated with column
  * number \a col_num of \a table.
  *
  * \return Positive on success, negative on errors.
@@ -2125,8 +2013,17 @@ int osl_get_nth_row(const struct osl_table *t, unsigned col_num,
 {
 	struct osl_column *col;
 	struct rb_node *node;
-	int ret = check_rbtree_col(t, col_num, &col);
+	unsigned num_rows;
+	int ret;
 
+	if (n == 0)
+		return -E_RB_KEY_NOT_FOUND;
+	ret = osl_get_num_rows(t, &num_rows);
+	if (ret < 0)
+		return ret;
+	if (n > num_rows)
+		return -E_RB_KEY_NOT_FOUND;
+	ret = check_rbtree_col(t, col_num, &col);
 	if (ret < 0)
 		return ret;
 	node = rb_nth(col->rbtree.rb_node, n);